1. Field of the Invention
The present invention relates to a structure of an electric panel circuit for an instrument panel of an automobile and a method for forming the same.
2. Statement of the Prior Art
A conventional electric circuit in an instrument panel of an automobile is formed such that a wiring harness formed in accordance with a predetermined electric circuit is manually laid out on the body of the automobile or on the dashboard of the instrument panel portion, and that the connectors of the wiring harness are then connected to connectors of switches and instruments.
However, in recent years, electronics have been used more and more in automobiles so as to have more sophisticated electric control, and the number of switches and instruments provided in the instrument panel portion for a driver has been remarkably increased, with the electric circuits becoming increasingly more complicated. Wiring harnesses used for forming electric circuits tend to become larger and heavier, and this tendency is expected to grow further in the future.
In accordance with the afore-mentioned means for laying out a wiring harness, a wiring harness comprising bundles of electric wires tied together that is long and large and is branched in many ways is manually laid out and fastened by means of clamps, and afterwards the connectors of the wiring harness need to be connected to connectors of switches and instruments. This requires space for laying out the wiring harness and for connecting connectors together.
However, as wiring harnesses become larger and more complicated, space available inside the dashboard becomes limited, which make the work of laying out a wiring harness and connecting connectors together very inefficient and difficult.
Furthermore, in accordance with the above means for forming a circuit, since electricity conduction tests on a group of electric circuits in the instrument panel portion can be carried out only when the electric circuits have been attached to the body of an automobile, when a failure in electricity conduction due to improper connection of connectors is found, large-scaled disassembling work is needed for repair. Thus, in the above means, there are problems of unstableness in quality (a risk of improper connection of connectors) based on the connector connecting means and large-scaled rectifications of failures. Moreover, the fact that it is not possible to produce electric circuits for an instrument panel portion in modules negative affects performance and productivity.
As electronics are used more and more in the instrument panel portion and electric circuits become more complicated, the difficulties inherent in the above-mentioned means for laying out a wiring harness will increase correspondingly, and the following problems are expected to result: production of defective articles due to improper connection of connectors; difficulties in securing space for laying out a wiring harness and connecting connectors together; and problems in the quality of wiring harnesses and the cost therefor due to the complication of wiring harnesses. In order to cope with this, a technical innovation in the means for constructing an electric circuit for the instrument panel portion of an automobile is strongly demanded in the relevant field.